uniform sampler2D src;
uniform float dx;
uniform float dy;

void main()
{
	vec4 color = texture2D(src, gl_TexCoord[0].xy);
	color += texture2D(src, gl_TexCoord[0].xy + vec2(dx,0.0));
	color += texture2D(src, gl_TexCoord[0].xy + vec2(dx,dy));
	color += texture2D(src, gl_TexCoord[0].xy + vec2(0.0,dy));
	color *= 0.25;
	gl_FragColor = color;
}